Apparatus for making sheets or films



Sept. 4, 1923.

A. F. SULZER ET AL APPARATUS FOR MAKING SHEETS 0R FILMS Filed Feb. 21, 1921 INVENTORS,

Z'J'Y/S WITNESSES:

ATTORNEY Patented Sept. 4, 1923.

,UNITED STATES PATENT OFFICE.

ALBERT F. SUEZER AND HENRY E. VAN DEBHOEF, OI ROCHESTER, NEW YORK,

ASSIGNORS '10 EASTMAN KODAK COMPANY, OF ROCHESTER, NEW YORK, A COR- PORATION OF NEW YORK.

. APPARATUS FOR MAKING SHEETS OR FILMS.

Application filed February 21, 1921. Serial No. 446,810.

To all whom it may concern:

Be it known that we, ALBERT F. SULZEB and HENRY E. VAN Dannonr, citizens of the United States of America, residing at Rochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements in Apparatus for Making Sheets or Films, of which the following is a full, clear, and exact specification.

This invention relates to apparatus and processes for making sheets or film from viscous compositions, known in the art as dopes, containing derivatives of cellulose, such as cellulose esters and cellulose ethers.

One object of our invention is to provide an apparatus of this kind with a dope receiving facing which will keep unimpaired in spite of use during long periods of time and Will not mechanically or chemically im part undesirable characteristics to the film formed thereon. Another object of our invention is to provide a process by which lengths of film may be made with certainty and without mechanical or chemical defects. Other objects will hereinafter appear. In the accompanying drawing,

Fig.' 1 is a diagrammatic side elevation, partly in section and on a reduced scale, of a typical film-making apparatus in which our invention may be embodied, certain parts being exaggerated in relative size for the sake of clearness.

Fig. 2 is a fragmentary sectional view of a facing embodying one form of our invention.

Cellulosic films, for example those which are used as supports for photographic coatings, are made from solutions of such a substance as cellulose nitrate, cellulose'aca tate, or cellulose'ether together with various modifying substances. An illustrative cellulose nitrate dope includes, for instance, fusel oiland a little camphor. with methyl alcohol and acetone as volatile solvents. Examples of typical cellulose acetate and cellulose ether dopes will be found in U. S. Patents Nos. 1,342,601, Seel, June 8, 1920, and 1,217,027, Lilienfeld, Feb. 20, 1917, respectively.

The dopes are customarily deposited in thin layers on smooth facings until enough of the volatile ingredients have evaporated to leave films that can be stripped olf. In earlier film-forming apparatus a dopespreadermoved over a horizontal facing of limited length. But in modern practice an endless dope-receiving facing, on a drum,

wheel or be't for example, travels successively past a dope-applying'station and a station where the film is removed, the dope on the facing setting into film while travelmg from the first station to the second.- In this way continuous strips of film are roduced that are not limited in length by the size of the facing. When returning from the film-removing station back to the dopeapplying station, the facing is usually cleaned by pads or brushes.

It will thus be seen that on every part of the facing an element of the continuous film is formed and stripped off during each cycle of movement of the facing. This action, repeated a very great number of times during long periods of time, subjects the facing to a severe test that tends to develop defects. A practical facing must effectively resist the formation of such defects.

Being formed in intimate contact with the facing, the film reproduces its surface, much as a. casting reproduces a mould. Con sequently if pits or line depressions, should be developed in the facing by reason of its repeated use, they would cause corresponding protubera-nces or ridges on one face of the film. Furthermore such pits or lines might expose small areas of metal underneath the facing. If such metal re-acts with the dope, it may form compounds in minute amounts, which, when carried on the film, may impair sensitive photographic coatings spread thereover.

In the case of nitroce lulose dopes, the defects have been generally resisted by using a facing of nickel-plated copper. But other cellulosic dopes, like cellulose acetate, are becoming of increasing importance and experience has shown that nickel-plated copper is not a durable or reliable facing for use with such dopes. It has become necessary, therefore, to find a new facing adapted to them, such facing for maximum utility being also usab e satisfactorily with the nitrate, ether and other dopes.

We have discovered that a facing, havin all the necessary'properties, may be forme by two superposed layers each composed of metal that is highly resistant to attack by the cellulose ester or ether dopes, the

inner 'layer reinforcing and supplementing the outer. A pair of adherin layers each composed of a metal of the fol owing group has been found efiicient, nickel, silver, gold, patinum, cobalt. Of course, alloys containing these in amounts to give the necessary properties would act equivalently. The preferred form comprises an outer pollshed layer of a harder metal, such as nickel, deposited on a layer of a precious metal, for example, silver. The latter is best when burnished or otherwise mechanically smoothed to close any minute openings or pores therein. Such a composite facing may, if desired, be located on a copper-plated iron Wheel or Manufacturing use of our new composite facin in comparison with the nickel-copper one demonstrates that our combination of metals has such an effect in the film-making process as to constitute virtually a novel ingredient thereof. The results are particularly unexpected as regards the resistance to the etched line defect. Harmless scratches of microscopic dimensions often appear on the facing, possibly from dust under the cleaning pads on brushes. The typical ace-- tate dope caused such tiny scratches in a nickel surface, when plated on copper, to rapidly grow until, in a few days, the cop-per layer was exposed through the etched lines thus formed. These lines caused ridges on the film, while the dope reacted with the copper to form substances which desensitized the photographic coating when later applied. On the contrary such scratches in the nickel did not grow or become harmful after weeks of continuous manufacturing use with the same dope when a nickel layer was located on a layer of precious metal, like silver. The theory underlying this surprising fact is not clear but electrochemical forces may be at work.

Under a powerful microscope a nickel layer appears somewhat rough or nodular. The nodular appearance grows as the plating thickens and the nodules can be flattened out and coalesced by mechanical smoothing only to a limited degree because of the hard ness of the metal. For use in dope-receiving facings the nickel layer is, therefore, usually a thin one to retain the requisite smoothness. Such a layer, when plated on copper and used with typical acetate dope for a few days, has small particles or nodules torn out, forming pits and exposing the copper beneath. But a nickel, layer of similar thickness, when plated on silver and used continuously for weeks with the same acetate dope, does not become pitted to any harmful extent. This is possibly due to the undoubtedly strong adherence between the silver and nickel, or the prevention of undermining of the nickel through corrosion of the sub-layer by liquid getting in through tiny pores or defects in the nickel, or to other action, but the fact of the superior c0- operat-ion is clear. If any silver should be exposed, it does not form substances that injure photographic emulsions or coatings. Moreover being ductile and smooth-plating, a relatively thick mechanically smoothed and coalesced layer of it. may be employed to supplement the harder nickel layer.

Referring now to the accompanying drawing, a. description in detail will be given of an illustrative embodiment of our invention, but the latter is, of course, not restricted to this embodiment or these details.

In Fig. 1 a base 1 supports a bearing 2 for the shaft 3 of a wheel or drum 4. The cylindrical peripheral facing 5 of the wheel moves during rotation in the direction of arrow 41 from a dope-applying station 6 to a film stripping or removing station 7 and then back to station 6 past a cleaning station.

At the dope applying station is a V- shaped through 61 having the usual adjustable gate 62 for regulating the thickness of the dope layer or coating that is deposited on facing 5. The film being drawn under tension away from the wheel 4, as indicated by arrow 71, passes over roller 72. The cleaning pad or roll 8 is carried in a swinging support 81 that is premed toward wheel 4 by a spring-pressed plunger 82.

All of these details are well known in the art and further explanation is, therefore, unnecessary. They illustrate the relation of our invention to the rest of a typical apparatus and process.

The facing 5 of wheel 4, as shown in Fig. 2, comprises three layers superposed on the main body 42 of the wheel. The periphery of the body or support 42, which is usually iron, is rough finished. A coating 51, of copper is then placed upon the periphery of body 42. lVhile we are not limited in the way the copper is applied, nevertheless, one method is to shrink a cylinder of copper onto body 42, grind it true and then polish it. Well known electro-deposition methods can also be used, with the usual mechanical surface treatment.

On the copper layer 51 is next electro-deposited a silver layer 52 using a standard silver plating bath, such as the cyanide type. The silver layer should be thick enough to be free from holes and imperfections and present a smooth surface after mechanical smoothing, such as burnishing. bufiing, etc. lVe prefer a rather heavy coating, say three ounces of silver per square foot.

Finally a layer of nickel 53 is deposited on the silver layer 52, using a nickel-ammonium sulfate bath or other usual solution. This layer is generally thinner than the silver layer, its thickness being carried to the point where it is as free from holes and imperfections as possible and yet sufficiently smooth to limit the size of nodules which become too high in thick platings. The nickel surface is polished as by buffing. In operation, the dope is deposited from trough G1 in a sheet of the desired thickness on our smooth peripheral facing. as the latter moves beneath the trough. The volatile solvents evaporate as the facing moves to station 7, causing the film to set to such firmness of strength that it can be removed over roller 72.

\Ve have found that the nickel may be on the inside and silver in contact with the dope with fair results, but we prefer to have the harder nickel on the outside.

Having thus described our invention, what we claim as new and desire'to secure by Letters Patent is:

1. In apparatus for the manufacture of film from cellulose ester and cellulose ether dopes, a member having a dope-receiving facing on which the film is made, said facing comprising superposed adherent layers, each composed of metal highly resistant to attack by said dopes under film-making conditions, the inner layer reinforcing the outer layer and supplementing the latter at any damaged points therein.

2. Apparatus for making film from cellulose ester and ether dopes for the support of light-sensitive photographic coatings, in-

. eluding a member having a dope-receiving facing on which the film is made. said facing comprising an outer metallic layer and an inner supplementary metallic layer, the metal of each layer being resistant to said dopes and not reacting therewith under filmmaking conditions to form substances 1n the film injurious to said photographic coatings.

3. An apparatus for the manufacture of film, a member having a dope-receiving facing on which the film is made, said facing comprising two superposed layers each composed of metal highly resistant to attack under film-making conditions, the inner layer being joined to the body of said member by an intermediate adherent metal bonding layer. 1

4. In apparatus for the manufacture of film from cellulose ester and cellulose ether dopes, a member having a dope-receiving facing on which the film is made, said coating comprising two superposed layers, one of them composed of a precious metal and the-other composed of a relativel harder metal resistant to said dopes un er filmmaking conditions.

5. In apparatus for the manufacture of film from cellulose ester and cellulose ether dopes, a member having a dope-receiving facing on which the film is ,made, said facing comprising superposed layers, one of which is composed of silver and the other of a relatively harder metal which is resistant. to said dopes under film-making conditions.

6. In apparatus for the manufacture of film from cellulose ester and cellulose ether dopes, a. member having a dope-receiving facing on which the film is made, said facing film, a member having a dope-receiving facing on which the film is made, said facing comprising superposed layers of nickel and silver.

9. In apparatus for the manufacture of film, a member having a dope receiving facing on which the film is made, said facing comprising superposed adherent layers, the outer one being composed of nickel and the inner one composed of a precious metal, the pores of which are closed.

10. In apparatus for the manufacture of film, a member having a dope-receiving facing on which the film is made, said facing comprising two superposed adherent layers, the outer layer being composed of buffed nickel and the inner layer being composed of burnished silver.

11. In apparatus for the manufacture of filmfrom cellulose ester and cellulose ether dopes, a member having a dope-receiving facing on which the film is made, said facing comprising superposed layers of a precious metal and a relatively harder metal resistant to said dopes under filmmaking conditions, one of said layers being joined to the body of said member by a smooth bonding coating.

12. In apparatus for the manufacture of film from cellulose ester and cellulose ether dopes, a member having a dope-receiving facing on which the film is made, said facing comprising two superposed layers, one of which is composed of silver and the other of a relatively harder metal resistant to said dopes under film-making conditions,

said silver layer being joined to the body of said member through an intermediate metallic bonding layer.

13. In apparatus for the manufacture of film, a member having a dope-receivin facing on which the film is made, said acing comprising superposed layers, one composed of nickel and the other of a precious metal, the latter being joined to the body of said member through a smoothed intermediate metallic coating.

14. In apparatus for the manufacture of film from cellulose ester and cellulose ether (lopes, a member having a dope-receiving facing on which the film is made, said member comprising, a smooth coating of copper having thereon superposed layers of a precious metal and a relatively harder metal resistant to said dopes under film-making conditions.

15. In apparatus for the manufacture of film from cellulose ester and cellulose ether dopes, a member having a dope-receiving facing on which the film is made, said member having a coating of copper on which is a facing comprising layers of silver and a relatively harder metal which is highly resistant to said dopes under film-making conditions.

16. In apparatus for the manufacture of film, a member having a dope-receiving fac ing on which the film is made, said facing comprising adherent layers of nickel and a precious metal on a copper base.

17. In apparatus for the manufacture of film, a member having a dope-receiving facing on which the film is made, said facing comprising adherent layers of nickel and silver on a copper base.

Signed at Rochester, New York, this 14th day of F ebruary, 1921.

ALBERT F. SULZER. H. E. VAN DERHOEF. 

